St Johns Hill School in Whanganui celebrated 90 years of education at its Parkes Ave site on Friday.
Pupils, teachers and a number of visitors were dressed in clothing that has been fashionable throughout the school's history.
After a kapa haka group performed a welcome for families and visitors, principal Michael Fitzgerald, dressed in cap and gown, held up a photo of the 1929 school opening.
Fitzgerald said when the school opened there were just 20 pupils and two classrooms.
"The school now has 17 classrooms and a roll of 412."